When no inquiry or application has been made by the claimant or a representative within 6 months, commencing with the day following the mailing of the item. In the case of insured mail with Canada, however, the time limit may be waived when it is satisfactorily established that the delay was unavoidable and not the fault of the claimant.

For an amount in excess of the maximum prescribed for the insurance or registry fee paid, unless responsibility rests with the United States and it is shown to the satisfaction of the Postmaster General that the sender was charged a fee less than that required to cover the amount of indemnity desired, through error on the part of the U.S. Postal Service. On such a showing, the deficiency in fee may be collected from the sender and postal indemnity paid, within the limit fixed for the higher fee.